“Levels of transparency within the savings industry are shockingly poor both in terms of transparency of fees and transparency of investments.”

Miller is expected to call on the Financial Services Authority (FSA) to “force or encourage” fund managers to reveal costs of trading.

In research over 1,000 individual UK pension funds, the group found a turnover of 128 per cent for the average portfolio. “SCM Private estimates that this adds 0.7 per cent in costs per year to an average UK pension fund, that is not disclosed to investors,” the report said.

Over 20 years of investing for retirement, the charges are the equivalent of “15 per cent of someone’s pension evaporating,” the group claimed.

“The average 15-year return of the unit trusts held in the individual pension funds was just 4.2 per cent per annum, so saving much of the needless dealing costs can increase returns substantially,” the report concluded.